The present invention relates to a method and device for determining the exposure dose of an electron beam required per pattern position to obtain a desired pattern in a coating.
In the manufacture of the latest generations of integrated circuits use is preferably made of focused electron beams in lithographic processes instead of making use of the usual optical lithographic techniques, since these latter techniques are subject to limitations in terms of resolution as a result of diffraction of the used laser light. The resolution of the integrated circuit obtained with such electron beam lithography is greater, although it is limited by scattering of the electrons in the coating. Methods are known for minimizing scattering effects or compensating therefor in advance and thereby improving the resolution of the obtained integrated circuits.
The known methods have the drawback however that scattering effects can themselves only be minimized to a limited degree, while advance compensation according to the known method requires many calculations and therefore needs a long calculation time. For the manufacture of integrated circuits for instance a very large number of pattern points, often in the order of magnitude of 1010 pattern points, must be “written”, while the number of calculations required for this purpose amounts to a multiple thereof. As a result a practically real time precompensation for the smearing or blurring effects cannot be implemented.
The object of the present invention is to obviate this drawback and also provide additional advantages.